My 25 Touring with 26 engine/transmission quickly developed a loud rattling noise when driving in low or reverse or stopped with clutch in. The noise stops completely when shifted into high gear. Any ideas?
When did this "quickly developed loud rattling noise" Start?
Was the engine/transmission recently worked on? Or have things been normal for a long time?
Can you explain what you mean by "stopped with clutch in"
I guess Kirby means "stopped with the clutch pedal halfway in"(or hand brake pulled)
Pull the transmission inspection door and check the triple gears, might be a problem with one of them?
Total tear down is likely necessary
When in high gear you take the triple gears out of play. Take the cover off the hog head and take a look at the triple gears. Grab them and see how much movement there is. Look at the teeth etc...Let us know what you find.
Another vote for triple gears.
I meant with the clutch pedal half way in and the car stopped the noise is very loud. The noise only goes away when car is in high gear. I have not recently done any thing to the transmission. The noise really started during a Horseless Carriage Rodeo at the San Diego County Fair. I did look in the transmission but didn't see anything unusual with triple gears or anything else.
Thanks guys for your input.
You have to grab the triple gears and feel how much play there is - did you turn the crank and check them all?
A triple gear pin is broke and one of the triple gears is floating. This is a tear down and fly wheel replacement.
Been there and done that.
Had a guy tell me the same thing last week, I told him to jack the rear end up and grab the left rear wheel, see if it moves in and out a 1/4 the babbit thrust washer are probably shot. Just fix his this eve and now no noise.
Roger, I will do all that when I get back home Sunday morning . Thanks.
Indeed rear axle noise can migrate through the drive shaft tube and appear to come from the transmission, but with a shot babbitt thrust in the rear the problem would appear in high too and when braking.
Friendly wager... I say triple gears...
Indeed it was the triple gear bushings. gears themselves are fine. now installing new bushings and pins. Thanks all.
Glad you found the problem... regards the pins...you need to remove some magnets and press them out Towards the magnet side, Not from the magnet side...Sure you know this, but bears repeating..
You then need to ream the triple gear bushings to 0.002" Running clearance which means 0.004"... Hope that makes sense, and that the forum guys and gals will agree....
I can't find Glen Chaffin's explanation as to why 0.004" clearance, but here is an excerpt from "Blueprinting a Model T" to be found here:
Transmission and Flywheel: Install new triple gear pins. Old ones wear egg shape 0.001" – 0.002".
Install new triple gear bushings and ream to 0.005" clearance. Check front flange on bushing clearance as outlined in the Ford Service Manual.
The low, reverse, and brake drum bushings clearance can be as loose as 0.005" – 0.010".
Over 0.010" clearance on the drum bushings is too sloppy. Ream new drum bushings to at least 0.005".
If reamed to 0.002" as specified for new bushings, the transmission may freeze up on a hot day before loosening up from break-in.
Ok, so its 0.004" to 0.005"
Anyway, I have had your issue happen to me.... and once where a transmission shaft bushing was set too tight, and it locked the car in High gear till it cooled off a bit.
I am also trying to find the specs on the thickness of the flange on the triple gear bushing.. but I'm not winning. Sure someone will help here...
All the best with your rebuild!
Very easy to understand. The .002" running clearance is .002 all the way around. So if you were to measure with a feeler gauge, (a wire one) on one side of the pin, you would have .004" When you insert the gauge, it would push the gear tight to one side and the result would be .004"
After having the bushings pressed in I would recommend having a machine shop hone the bushings in a vertical machine to assure they are straight. Reaming requires a trained hand and there is a risk of taking too much off.